This disclosure relates generally to maintaining a component and, more particularly, to monitoring an electrical input current of a device to effectively time a maintenance action on the component.
Complex assemblies, such as turbomachines, include various individual components. Some of the individual components include portions that move in response to an applied electrical input current. Such movement is needed to move variable geometry blades within a turbomachine, for example.
An example component may include an electromechanical servovalve (EHSV) and an actuator. The null bias electrical current of the EHSV is the electrical current input that is needed to overcome the actuator null effect, or cause the actuator to maintain a steady state position. If the input current is larger than the null bias current, then the current will open the EHSV and port more fluid to the actuator, which drives the actuator to a desired extended position. Components are designed so that the current required to overcome the null bias and move the component to a desired position falls within a normal range of industry standards. A range of electrical input current is specified, rather than an exact value, because of build tolerances and other variables. The EHSV is typically biased to return to the home (or null) position when the current is not applied. Biasing the EHSV to the home position ensures that the EHSV is in a known position when no current is applied.
In this example, extending and retracting the actuator of the component moves the variable geometry blade within a turbomachine.